POLYURETHANE FOAM FOR ULTRALOW TEMPERATURE COLD INSULATION AND ITS PRODUCTION

PROBLEM TO BE SOLVED: To obtain a polyurethane foam for ultralow temperature cold insulation exhibiting an excellent heat insulating property and a mechanical property even at an ultralow temperature, and to provide its producing method. SOLUTION: This polyurethane foam is obtained by reacting a polyol component with an isocyanate component in the presence of a foaming agent, a reaction catalyst, a pore stabilizer and other additives. In the foam, the polyol component contains 20-60 wt.% of a polyether polyol obtained by adding propylene oxide and ethylene oxide to sorbitol, 10-40 wt.% of a polyether polyol obtained by adding propylene oxide and ethylene oxide to pentaerythritol, 10-20 wt.% of a polyether polyol obtained by adding propylene oxide and ethylene oxide to sucrose, 10-20 wt.% of a polyester polyol obtained by adding propylene oxide and ethylene oxide to phthalic anhydride, and 10-20 wt.% of a polyester polyol obtained by adding propylene oxide and ethylene oxide to bisphenol-A, and the isocyanate component is a polymer type 4,4'-diphenylmethane diisocyanate having 2.7-3.1 functional group number. By the method, the foam exhibits excellent mechanical strength even at an ultralow temperature.